JP6026051B1 - CPU unit, target unit and PLC system - Google Patents

Abstract

A first system bus input / output circuit unit 11 for inputting / outputting signals, an extended function control circuit unit 12 for communicating with an extended function circuit unit 22 provided in the target unit 3, and a first system bus input / output circuit unit 11 or the extended function control circuit unit 12 is switched to be connected to the first signal line B1 included in the system bus B, and the extended function control circuit unit 12 is provided in the target unit 3. When communication is performed with the extended function circuit unit 22, a CPU unit that connects the extended function control circuit unit 12 and the first signal line B <b> 1 to the switching unit 13 is provided. In a configuration where the extended function unit shares the same signal line with other components, even if the signal changes due to the influence of the external environment, the extended function unit and other components may communicate without confusion with the signal. it can.

Description

  The present invention relates to a CPU unit, a target unit, and a PLC system that perform communication via a system bus.

  The building block type PLC (Programmable Logic Controller) is a PLC constructed by combining a CPU (Central Processing Unit) unit and a plurality of target units based on the control scale and control contents of the controlled device. In this configuration, the CPU unit communicates with one or a plurality of target units connected via a system bus.

  In addition, there is a case where it is desired to newly expand functions in a system using a PLC used in production equipment and production equipment. In the following description, a function unit to be newly expanded is referred to as an expanded function unit. In addition, as functions to be newly expanded, there are an inter-unit synchronization function and a high-speed serial communication function that synchronize operation timing between units.

  Here, a method of reconstructing as a new system provided with an extended function unit is conceivable. However, in this method, all the units of the PLC in the production facility and production apparatus that are currently used must be replaced, and there is a problem that the cost and labor of updating the system are required.

  On the other hand, there is a method of newly adding an extended function unit to the system or exchanging system components for the extended function unit. In the case of this method, there is an advantage that the cost and labor of system update can be reduced compared with the method of reconstructing the system described above, but it is necessary to secure a signal line in order to use the extended function unit. .

  Here, when there is an empty signal line on the system bus, an empty signal line can be assigned to the extended function unit, but when there is no empty signal line, it is assigned to another component. A configuration may be considered in which the signal line used is shared with the extended function unit.

  Patent Document 1 discloses a configuration in which an extended function unit is added to a system and signal lines assigned to other components are shared with the extended function unit. Specifically, in Patent Document 1, a CPU module having an input / output bus interface is equipped with a high-speed serial bus interface as an extended function unit, and the high-speed serial bus interface is connected to the same input / output bus as the input / output bus interface. Thus, a configuration for sharing an input / output bus is disclosed.

  Patent Document 1 discloses that an input / output bus and an input / output module with a high-speed serial bus interface communicate serially, and an input / output bus uses an input / output bus interface and a normal input / output module. A configuration for performing parallel communication is also disclosed.

JP 2006-133924 A

  By the way, in Patent Document 1, even in a configuration in which a CPU unit, a target unit for parallel communication, and a target unit for serial communication are connected on the same bus, the bus is used in parallel communication and serial communication. Since the cycle frequency is different, it is described that the signal for parallel communication is not input to the target unit for serial communication, and that the signal for serial communication is not input to the target unit for parallel communication. ing.

  However, since a system using PLC is incorporated in production facilities and production apparatuses and used in various environments, it is conceivable that signals transmitted and received between units change due to the influence of the external environment. The influence of the external environment is the influence of vibration and electromagnetic noise applied to the system.

  In other words, in a configuration in which the extended function unit shares the same signal line with other components, the signal changes due to the influence of the external environment, and the extended function unit receives signals from other components, or other configurations. There is a possibility that confusion will occur when an element receives a signal of an extended function unit. Further, when signals are confused and malfunctions occur, communication cannot be established between the units constituting the PLC, and the expanded function cannot be executed.

  The present invention has been made in view of the above, and in the configuration in which the extended function unit shares the same signal line with other components, even if the signal changes due to the influence of the external environment, the extended function unit and It is an object of the present invention to provide a CPU unit in which other components can communicate without confusing signals.

In order to solve the above-described problems and achieve the object, the present invention provides a CPU unit connected to a target unit via a system bus, a first system bus input / output circuit unit that inputs and outputs signals, a target An extended function control circuit unit that communicates with an extended function circuit unit provided in the unit, and a first system bus input / output circuit unit or an extended function control circuit unit are connected to a first signal line included in the system bus. A first switching unit that switches so that the extended function control circuit unit communicates with the extended function circuit unit included in the target unit when the extended function control circuit unit communicates with the first switching unit. when allowed to connect the first signal line, without any communication with the extensions circuit unit that has been provided to the Turn-target units, said the first switching unit first system bus output circuit portion and the first signal Characterized in that to connect the line.

  In the CPU unit according to the present invention, in the configuration in which the extended function unit shares the same signal line with other components, even if the signal changes due to the influence of the external environment, the extended function unit and the other components transmit the signal. You can communicate without confusion.

Configuration diagram of PLC system according to embodiment Configuration diagram when the setting of the extended function of the PLC system is valid Configuration diagram when the setting of the extended function of the PLC system is invalid The figure which serves for explanation about the change procedure of the change part The signal waveform of the system bus input / output circuit unit and the signal waveform of the extended function control circuit unit and the extended function circuit unit when the CPU unit and the extended function compatible target unit for which the extended function setting is effective communicate. Figure Flow chart for explaining the operation of the PLC system

  Hereinafter, a CPU (Central Processing Unit) unit, a target unit, and a PLC (Programmable Logic Controller) system according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment FIG. 1 is a diagram showing a PLC system 1 in which a CPU unit 2 and a target unit 3 according to an embodiment of the present invention are connected via a system bus B. In FIG. 1, three target units are connected to the system bus B, but the number is not limited to three. Although details will be described later, the target unit 3 includes an extended function compatible target unit 3a corresponding to the extended function and an extended function non-compatible target unit 3b not corresponding to the extended function.

  The configuration of the CPU unit 2 will be described. The CPU unit 2 is connected to the target unit 3 via the system bus B, and includes a system bus input / output circuit unit 11 as a first system bus input / output circuit unit for inputting and outputting signals, an extended function circuit unit, An extended function control circuit unit 12 that performs communication, and a switching unit 13 as a first switching unit that switches between the system bus input / output circuit unit 11 or the extended function control circuit unit 12 are provided.

  The system bus B is composed of a plurality of signal lines. The signal lines B1 are included in the plurality of signal lines. The signal line B1 is used for communication performed between the CPU unit 2 and the target unit 3, and a signal indicating an execution state of communication such as an output enable signal and an input enable signal is transmitted.

  The extended function control circuit unit 12 communicates with the extended function circuit unit provided in the target unit 3.

  Specifically, when the extended function control circuit unit 12 performs communication with the extended function circuit unit provided in the target unit 3, the extended function control circuit unit 12 and the signal line B1 are connected to the switching unit 13. Connect.

  When connected to the signal line B1, the extended function control circuit unit 12 transmits an input / output invalid signal that invalidates the input / output of the signal line B1 to the target unit 3 that does not include the extended function circuit unit.

  Further, when the extended function control circuit unit 12 does not communicate with the extended function circuit unit included in the target unit 3, the extended function control circuit unit 12 causes the switching unit 13 to connect the system bus input / output circuit unit 11 and the signal line B1.

  The switching unit 13 performs switching so that the system bus input / output circuit unit 11 or the extended function control circuit unit 12 is connected to the signal line B1.

  Therefore, the CPU unit 2 communicates with the extended function circuit unit provided in the target unit 3 in a configuration in which the extended function control circuit unit 12 shares the same signal line B1 as the system bus input / output circuit unit 11. Since either the system bus input / output circuit unit 11 or the extended function control circuit unit 12 is connected to the signal line B1 based on whether or not to perform the operation, even if the signal changes due to the influence of the external environment, the system bus The input / output circuit unit 11 and the extended function control circuit unit 12 can communicate without confusing signals.

  Further, when the extended function control circuit unit 12 is connected to the signal line B1 and the extended function is used, the CPU unit 2 transmits an input / output invalid signal to the target unit 3 that does not include the extended function circuit unit. Even if the signal changes due to the influence of the external environment, the system bus input / output circuit unit 11 is not affected.

  Next, the configuration of the target unit 3 will be described. Specifically, the target unit 3 is a signal input unit, a signal output unit, and a positioning unit. What is necessary is a system bus input / output circuit unit 21, an extended function circuit unit 22, and a switching unit 23, which will be described later. A target unit may be used. The target unit 3 includes an extended function compatible target unit 3a corresponding to the extended function and an extended function non-compatible target unit 3b not corresponding to the extended function.

  The extended function compatible target unit 3a includes a system bus input / output circuit unit 21 as a second system bus input / output circuit unit that inputs and outputs signals, an extended function circuit unit 22 that executes an extended function, and a system bus input And a switching unit 23 as a second switching unit that switches the output circuit unit 21 or the extended function circuit unit 22.

  The switching unit 23 switches so that the system bus input / output circuit unit 21 or the extended function circuit unit 22 is connected to the signal line B1.

  The extended function non-corresponding target unit 3b includes a system bus input / output circuit unit 31 for inputting and outputting signals. In addition, when the CPU unit 2 and the extended function compatible target unit 3a are connected to the signal line B1 and communicate with each other, the extended function non-compatible target unit 3b inputs and outputs from the extended function control circuit unit 12 of the CPU unit 2. Receive an invalid signal.

  Here, the operation of the extended function control circuit unit 12 will be described with reference to FIGS. FIG. 2 is a configuration diagram when the setting of the extended function is valid. FIG. 3 is a configuration diagram when the setting of the extended function is invalid.

  The extended function control circuit unit 12 starts reading the model information of the target unit 3 connected to the system bus B at the timing when the PLC system 1 is activated. Then, the extended function control circuit unit 12 recognizes all the target units 3 connected to the system bus B, sets the target unit 3 to the extended function compatible target unit 3a in which the extended function setting is valid, and sets the extended function. Is divided into an extended function compatible target unit 3a and an extended function non-compatible target unit 3b.

  When the extended function control circuit unit 12 communicates with the extended function compatible target unit 3a in which the setting of the extended function is valid, the extended function control circuit unit 12 is connected to the switching unit 13 as shown in FIG. Are connected to the signal line B1. Further, the extended function control circuit unit 12 causes the switching unit 23 to connect the extended function circuit unit 22 of the extended function compatible target unit 3a and the signal line B1. Further, the extended function control circuit unit 12 transmits an input / output invalid signal for invalidating the input / output of the signal line B1 to the target unit 3b not supporting the extended function.

  Therefore, the PLC system 1 includes the system bus input / output circuit unit 11, the system bus input / output circuit unit 21, and the system bus input / output circuit unit 31, and the newly added extended function control circuit unit 12 and extended function circuit unit 22. In the configuration in which the same signal line B1 is shared, communication can be performed without confusion between the extended function control circuit unit 12 and the extended function circuit unit 22 even if the signal changes due to the influence of the external environment. . The PLC system 1 can secure the same reliability as before the function expansion even after the function expansion, and can perform a stable operation.

  Further, when the extended function control circuit unit 12 performs communication between the extended function compatible target unit 3a and the extended function non-compatible target unit 3b in which the setting of the extended function is invalid, as shown in FIG. The switching unit 13 connects the system bus input / output circuit unit 11 and the signal line B1. The extended function control circuit unit 12 connects the switching unit 23 to the system bus input / output circuit unit 21 of the extended function compatible target unit 3a and the signal line B1. In addition, the extended function control circuit unit 12 transmits a release signal for canceling the invalidation of the input / output of the signal line B1 to the target unit 3b not supporting the extended function. When the system bus input / output circuit unit 11 and the signal line B 1 are connected by the switching unit 13, the extended function control circuit unit 12 uses a bus between the system bus input / output circuit unit 11. Thus, the signal line B1 is monitored via the system bus input / output circuit unit 11. When the extended function is used, the extended function control circuit unit 12 controls the switching unit 13 so that the extended function control circuit unit 12 is connected to the signal line B1, and the extended function circuit unit 22 is connected to the signal line B1. The switching unit 23 is controlled as described above.

  Therefore, the PLC system 1 includes the system bus input / output circuit unit 11, the system bus input / output circuit unit 21, and the system bus input / output circuit unit 31, and the newly added extended function control circuit unit 12 and extended function circuit unit 22. In the configuration sharing the same signal line B1, even if the signal changes due to the influence of the external environment, a signal is transmitted between the system bus input / output circuit unit 11, the system bus input / output circuit unit 21, and the system bus input / output circuit unit 31. You can communicate without confusion. The PLC system 1 can secure the same reliability as before the function expansion even after the function expansion, and can perform a stable operation.

  Further, the extended function control circuit unit 12 monitors communication between the CPU unit 2 and the extended function compatible target unit 3a. When the extended function control circuit unit 12 starts communication between the CPU unit 2 and the extended function compatible target unit 3a in which the extended function setting is valid, the communication is started and the signal line B1 is in a significant state. After confirming the change, the switching unit 13 is connected to the extended function control circuit unit 12 of the CPU unit 2 and the signal line B1, and the switching unit 23 is connected to the extended function circuit unit 22 of the extended function compatible target unit 3a. Are connected to the signal line B1.

  Below, the specific switching procedure of the switching part 13 is demonstrated using FIG. One of the switching units 13 is grounded, the other is connected to or disconnected from the system bus input / output circuit unit 11, one is connected to the signal line B1, and the other is connected to the system bus. And a switching terminal 13b connected to the input / output circuit unit 11 or the extended function control circuit unit 12.

  As shown in FIG. 4A, the switching unit 13 is connected to the system bus input / output circuit unit 11 and the signal line B1 through a switching terminal 13b, and the ground terminal 13a is connected to the system bus input / output circuit unit 11. In the case where the extended function control circuit unit 12 and the signal line B1 are connected from the state where there is not, the connection state between the system bus input / output circuit unit 11 and the signal line B1 is maintained as shown in FIG. The ground terminal 13a is switched so that the system bus input / output circuit unit 11 is connected to the ground. Next, as illustrated in FIG. 4C, the switching unit 13 switches the switching terminal 13b so that the extended function control circuit unit 12 and the signal line B1 are connected.

  Therefore, the switching unit 13 switches the system bus input / output circuit unit 11 without releasing it when connecting the extended function control circuit unit 12 and the signal line B1. The switching procedure of the switching unit 23 is the same as that of the switching unit 13 described above.

  Further, when the communication between the CPU unit 2 and the extended function compatible target unit 3a in which the extended function setting is valid ends, the extended function control circuit unit 12 confirms that the communication has ended. The switching unit 13 connects the system bus input / output circuit unit 11 of the CPU unit 2 and the signal line B1.

  Specifically, as shown in FIG. 4C, the switching unit 13 is connected to the extended function control circuit unit 12 and the signal line B1 through the switching terminal 13b, and the ground terminal 13a is connected to the system bus input / output circuit unit 11. When the system bus input / output circuit unit 11 and the signal line B1 are connected from the state where they are connected to each other, as shown in FIG. 4B, the connection state between the ground and the system bus input / output circuit unit 11 is maintained. The switching terminal 13b is switched so that the system bus input / output circuit unit 11 and the signal line B1 are connected. Next, as shown in FIG. 4A, the switching unit 13 switches the ground terminal 13a and the system bus input / output circuit unit 11 to a non-connected state.

  Therefore, when connecting the system bus input / output circuit unit 11 and the signal line B1, the switching unit 13 performs switching so that the signal state of the system bus input / output circuit unit 11 can be maintained. The switching procedure of the switching unit 23 is the same as that of the switching unit 13 described above.

  FIG. 5A shows signal waveforms of the system bus input / output circuit unit 11 and the system bus input / output circuit unit 21 when the CPU unit 2 communicates with the extended function compatible target unit 3a in which the setting of the extended function is valid. FIG. T1 in FIG. 5A indicates the communication period of the CPU unit 2 and the extended function compatible target unit 3a in which the setting of the extended function is valid. T2 in FIG. 5A is an operation period of the switching unit 13 for switching from the system bus input / output circuit unit 11 to the extended function control circuit unit 12, and switching for switching from the system bus input / output circuit unit 21 to the extended function circuit unit 22 The period which totaled the operation period of the part 23 is shown. T3 in FIG. 5A indicates the operation period of the switching unit 13 for switching from the extended function control circuit unit 12 to the system bus input / output circuit unit 11, and the switching for switching from the extended function circuit unit 22 to the system bus input / output circuit unit 21. The period which totaled the operation period of the part 23 is shown.

  FIG. 5B is a diagram illustrating signal waveforms of the extended function control circuit unit 12 and the extended function circuit unit 22. T4 in FIG. 5B indicates the effective period of the extended function. The effective period of the extended function is a period from the elapse of T2 to the start of T3.

  Therefore, the PLC system 1 is newly added between the system bus input / output circuit unit 11, the system bus input / output circuit unit 21, and the system bus input / output circuit unit 31 in a configuration in which the same signal line B1 is shared. Communication between the function control circuit unit 12 and the extended function circuit unit 22 can be achieved without confusion of signals.

  Next, a specific operation of the PLC system 1 will be described with reference to a flowchart shown in FIG.

  In step S1, the PLC system 1 is activated.

  In step S2, the extended function control circuit unit 12 starts reading the model information of all target units 3 connected to the system bus B by bus access.

  In step S3, the extended function control circuit unit 12 determines whether the extended function of each target unit 3 is supported or not based on the model information read in step S2. That is, the extended function control circuit unit 12 determines whether the target unit 3 is the extended function compatible target unit 3a or the extended function non-compatible target unit 3b.

  In step S4, the extended function control circuit unit 12 checks the extended function setting parameters set by the user based on the model information read in step S2. In the extended function compatible target unit 3a, it is assumed that the extended function setting parameter is set based on whether the extended function is enabled or disabled before the PLC system 1 is activated by the user.

  In step S5, the extended function control circuit unit 12 determines whether the setting of the extended function is valid as a result of the check in the step S4. If the setting of the extended function is valid (Yes), the process proceeds to step S6. If the setting of the extended function is not valid (No), that is, if the setting of the extended function is invalid, the process proceeds to step S11.

  In step S6, the extended function control circuit unit 12 determines whether or not the target unit 3 is the extended function compatible target unit 3a as a result of the determination in the step S3. If it is the extended function compatible target unit 3a (Yes), the process proceeds to step S7, and if it is not the extended function compatible target unit 3a (No), that is, if it is the extended function non-compatible target unit 3b, the process proceeds to step S10. .

  In step S7, the extended function control circuit unit 12 transmits the parameter validity information to the extended function compatible target unit 3a in which the extended function setting is valid.

  In step S8, the extended function control circuit unit 12 causes the switching unit 13 to connect the extended function control circuit unit 12 and the signal line B1.

  In step S9, the extended function control circuit unit 12 transmits a signal via the signal line B1.

  In step S10, the extended function control circuit unit 12 transmits an input / output invalid signal for invalidating the input / output of the signal line B1 to the target unit 3b that does not support the extended function.

  In step S11, the extended function control circuit unit 12 connects the system bus input / output circuit unit 11 and the signal line B1 to the switching unit 13, and the extended function corresponding target unit 3a in which the setting of the extended function is invalid in the switching unit 23. The system bus input / output circuit unit 21 and the signal line B1 are connected to invalidate the setting of the extended function.

  Therefore, in the PLC system 1, the system bus input / output circuit unit 11, the extended function control circuit unit 12, the system bus input / output circuit unit 21, the extended function circuit unit 22, and the system bus input / output circuit unit 31 have the same signal line B1. When the setting of the extended function is valid in the configuration sharing the network, communication using the extended function can be performed between the extended function control circuit unit 12 and the extended function circuit unit 22 using the signal line B1. it can.

  In the PLC system 1, the system bus input / output circuit unit 11, the extended function control circuit unit 12, the system bus input / output circuit unit 21, the extended function circuit unit 22, and the system bus input / output circuit unit 31 have the same signal line B1. If the setting of the extended function is enabled in the configuration sharing the I / O, an input / output invalid signal for invalidating the input / output of the signal line B1 is transmitted to the target unit 3b that does not support the extended function. Even if the signal changes due to the influence, the system bus input / output circuit section 31 is not affected.

  In the PLC system 1, the system bus input / output circuit unit 11, the extended function control circuit unit 12, the system bus input / output circuit unit 21, the extended function circuit unit 22, and the system bus input / output circuit unit 31 have the same signal line B1. When the setting of the extended function is invalid in the configuration sharing the system bus I / O circuit unit 11, the system bus I / O circuit unit 21, and the system bus I / O circuit unit 31 using the signal line B1. Can communicate.

  Furthermore, the PLC system 1 allows the system to be reconstructed by replacing all the units used in the production facility and the production apparatus even when the signal lines constituting the system bus are not available in the function expansion. Therefore, it is possible to add only the part of the unit that affects the expansion of the function, and it is possible to reduce the cost and man-hour for updating the system.

  The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

  1 PLC system, 2 CPU unit, 3 target unit, 3a extended function compatible target unit, 3b extended function non-compatible target unit, 11, 21, 31 system bus input / output circuit section, 12 extended function control circuit section, 13, 23 switching Part, 22 extended function circuit part.

Claims (4)

In the CPU unit connected to the target unit via the system bus,
The CPU unit is
A first system bus input / output circuit unit for inputting / outputting signals;
An extended function control circuit unit that communicates with an extended function circuit unit provided in the target unit;
A first switching unit configured to switch the first system bus input / output circuit unit or the extended function control circuit unit to be connected to a first signal line included in the system bus;
When the extension function control circuit unit performs communication with the extension function circuit unit included in the target unit, the extension function control circuit unit and the first signal line are connected to the first switching unit. connected to the case where said extensions circuit unit provided in the target unit does not communicate, Rukoto to connect the first system bus output circuit portion and the first signal line to the first switching unit CPU unit characterized by this.   The extended function control circuit unit, when connected to the first signal line, transmits an input / output invalid signal of the first signal line to a target unit that does not include the extended function circuit unit. CPU unit. In the target unit connected to the CPU unit according to claim 1 via a system bus,
The target unit includes an extended function compatible target unit corresponding to the extended function and an extended function non-compatible target unit not compatible with the extended function.
The extended function compatible target unit is:
A second system bus input / output circuit for inputting and outputting signals;
Extended function circuit section;
A second switching unit for connecting the second system bus input / output circuit unit or the extended function circuit unit and the first signal line ;
The extension function control circuit unit connects the extension function circuit unit and the first signal line to the second switching unit when performing communication between the extension function control circuit unit and the extension function circuit unit. the case of no communication between the extension control circuit portion and the extension circuit, Rukoto to connect the said second system bus output circuit portion and the first signal line to the second switching unit Target unit characterized by A PLC system, wherein the CPU unit according to claim 1 and the target unit according to claim 3 are connected via a system bus.

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